Five asylum seekers are launching a legal challenge this week which could change the way detention centres are run.

The men are calling for an immediate suspension of “lock in” procedures and an overhaul of unsanitary toilets and poor ventilation inside the cells at Brook House immigration removal centre near Gatwick airport.

The legal challenge, a judicial review which will be heard in the high court on Friday, will ask for an immediate suspension of lock-in procedures that can see the men locked in their cells for 13 hours a day. Lawyers for the five men are also asking for all to be released or transferred.

The judicial review also focuses on the insanitary toilets in shared cells which are not separated from beds by a curtain or a screen and have neither seats nor covers. Because of poor ventilation in the rooms the men say the smell from the toilets is intolerable and that they feel shame urinating or defecating in front of their roommates. Sixty cells in Brook House can accommodate three people.

The centre was recently exposed by Panorama for abusive tactics by staff of G4S, the private security company which runs it.

Lottie Hume, a caseworker at Duncan Lewis and part of the team involved with the legal challenge, said: “This is a daily living nightmare for everyone locked in Brook House, languishing in conditions that breach their human rights. BBC’s Panorama exposé allowed a glimpse into Brook House, but … the documentary was unable to capture the full horror of the situation.

“Our clients speak with damning consistency on life in the centre: the draconian lock-in regime, appalling room conditions, overcrowding, limited healthcare, poor hygiene facilities, segregation, an abusive staff culture … the list is endless. These issues are not isolated; they are a complex mess that the Home Office can no longer ignore.”

The men, who have fled persecution in Afghanistan, (where two of the five are from) Ethiopia, Sri Lanka and Bangladesh, say they are locked in their rooms for more than 13 hours per day.

The regime in detention centres is supposed to be more relaxed than in prisons and some detention centres use “lock-ins” far less than at Brook House.

Some of the men are Muslim and say it is impossible to pray properly in their cells because of the toilets. Islam stipulates that prayers should be conducted in a spotlessly clean environment.

One of the men, a 20-year-old from Afghanistan, who was subjected to a kidnap attempt by the Taliban at the age of 17, said he tried not to use the toilet in the cell he was sharing with others because he felt ashamed.

He prays five times a day and said Mecca and the toilet face the same direction so his prayer mat touches the toilet, something his religion does not permit. He described the conditions as “insulting and offensive”.